activate noclip mode only after checkpoint

[stefanofossati]

now the noclip mode can be activated even if the player haven't activated the checkpoint yet: it's better that the noclip mode can be activated only if the player has activated the checkpoint

[spig95]

Is this feature still needed? For the area-00 tutorial, I think that we can simply deactivate the noclip enabler box collider from the first checkpoints, and enable it once the player needs to noclip.

If you need this feature for following areas, I can implement a minor change to AnchorCheckpointController